Patent Literature 1 discloses a superconducting circuit protecting device, and a superconducting magnet device. The devices include a small forcing quench heater, induction coils which recover magnetic energy by magnetic induction, when quench occurs, and a blackout (electric power failure) detector. When the blackout detector detects blackout, the superconducting coils are forced to be quenched by the small forcing quench heater and the magnetic energy is recovered by the induction coils, before the induction coils are changed into a state in which they are unable to recover the energy due to an increase in a resistance with a temperature increase. This allows the superconducting circuit to be protected from the quench during the blackout (abstract).
Patent Literature 2 discloses a high-temperature superconducting magnet. This magnet includes high-temperature superconducting coils in which a plurality of coil units formed by winding electric conductors made of high-temperature superconducting wire material are stacked together, and is configured such that a heat conductive member provided with a heater is inserted into a region between the coil units (claim 5).